Age-related macular degeneration (AMD) is a highly prevalent, multifactorial, polygenic complex disease. It is now widely accepted that inflammation and the immune system play a direct role in the pathogenesis of AMD. As inflammation builds up in aging and, much more so, in AMD, we hypothesize that a vicious cycle is set in motion that exposes macular tissues to an increasing amount of inflammatory and immune-mediated damage. We propose that this mechanism is critical to AMD development and progression. We have strong evidence that patients with early and advanced AMD express auto-antibodies (auto-Abs) against macular human tissue antigens significantly more commonly and more intensely than elderly controls. However, having shown this does not prove that the auto-Abs have a direct role in contributing to disease development and/or progression. To understand the role of auto-Abs in AMD, it is essential to discover the identity of their targets, and provide prof of a causal link between disease and presence of auto-Abs. To tackle these critically important questions, we propose the following series of Aims: 1) To discover the identity of all statisticall significant macular antigens identified in our preliminary investigations and test the hypothesis that wild-type (WT) mice immunized against these antigens develop auto-Abs towards them and changes consistent with an AMD phenotype. 2) To test the hypothesis that auto-Abs that develop in an early-onset murine model of AMD can be used to accelerate disease appearance and increase its severity in a late-onset model via adoptive transfer of serum IgG. 3) To test the hypothesis that similar autoimmune reactivity patterns occur not only across species but also across animal models of AMD, and to establish a relationship between time course of auto-Ab development and time of onset of phenotypes. These studies will allow us to discover targets of autoreactivity in AMD, investigate commonalities (and differences) across species and models, test the causality of the autoimmune hypothesis in AMD, define an autoreactivity sequence, identify early disease markers and progression risk markers, and develop a much more refined pathogenic framework for the role of autoimmunity in AMD. We predict that these studies will ultimately pave the way toward using the existing AMD models and those that we plan to induce to investigate and develop new treatments for the manifestations of AMD, and that it will be possible to translate these treatments back to bedside in human clinical trials.